Optical displacement sensor and external force detecting device

Abstract

An optical displacement sensor comprises: a light source; a light receiving means adapted to receive light emitted from the light source; and a light diffracting element disposed between the light source and the light receiving means. The light receiving means include a first light receiving element group centrally located, and a second light receiving element group constituted by two separate clusters disposed so as to sandwich the first light receiving element group, and the light diffracting element functions to diffract the light emitted from the light source along one direction of the two-axis directions into a zero-order beam to be received at the first light receiving element group, and higher-order beams received at the second light receiving element group.

Description

[0001]This application claims priority from Japanese Application No. 2003-316478, filed Sep. 9, 2003 (incorporated by reference herein).BACKGROUND OF THE INVENTION[0002]1. Field of the Invention[0003]The present invention relates to an optical displacement sensor and an external force detecting device, and particularly to an optical displacement sensor which detects relative displacement between a reference object and a measurement object based on displacement of a light reception position, and further to an external force detecting device which detects an external force applied to the measurement object based on a signal outputted from the optical displacement sensor.[0004]2. Description of the Related Art[0005]An external force detecting device, such as a six-axis optical force sensor, is conventionally known, in which a displacement amount of an action section to receive an external force, namely a measurement object, relative to a support section to support the action section, n...

AI Technical Summary

Benefits of technology

[0012]The present invention has been made in light of the above problem, and it is an object of the present invention to provide an optical displacement sensor, and an external force detecting device, in which a position of a light receiving means relative to a light source with respect to a rotational direction about an optical axis of light emitted from the light source can be adjusted easily in a reduced time.

[0019]According to a fifth aspect of the present invention, there is provided a method of adjusting such an optical displacement sensor as structured according to the first aspect of the present invention. The method comprises a step of adjusting a position of the light receiving means relative to the light source with respect to a rotational direction about the optical axis of the light emitted from the light source based on a reception state of the higher-order beams at the second light receiving element group. Consequently, the optical displacement sensor can be adjusted without troublesome work in a reduced time.

[0020]According to a sixth aspect of the present invention, there is provided a method of adjusting such an optical displacement sensor as structured according to the second aspect of the present invention. The method comprises a step of adjusting a position of the light receiving means relative to the light source with respect to a rotational direction about the optical axis of the light emitted from the light source based on a reception state of the light at the light receiving means. Consequently, the optical displacement sensor can be adjusted easily without provision of the light diffracting element and the second light receiving element group used in the first aspect.

[0021]According to a seventh aspect of the present invention, there is provided a method of adjusting such an optical displacement sensor as structured to the third aspect of the present invention. The method comprises a step of adjusting a position of the light receiving means relative to the light source with respect to a rotational direction about the optical axis of the light emitted from the light source based on a reception state of the higher-order beams at the second light receiving element group. Consequently, the optical displacement sensor structured to include the reflector member can be also adjusted without troublesome work in a reduced time.

[0022]According to an eighth aspect of the present invention, there is provide a method of adjusting such an optical displacement sensor as structured according to the fourth aspect of the present invention. The method comprises a step of adjusting a position of the light receiving means relative to the light source with respect to a rotational direction about the optical axis of the light emitted from the light source based on a reception state of the light at the light receiving means. Consequently, the optical displacement sensor provided with the reflector member can be adjusted easily without provision of the light diffracting element and the second light receiving element group used in the third aspect.

[0023]According to a ninth aspect of the present invention, an external force detecting device is provided which incorporates an optical displacement sensor structured according to any one of the aforementioned first to fourth aspects, and an external force applied to a measurement object is detected based on a signal containing a measurement result by the optical displacement sensor. In the ninth aspect of the present invention, the optical displacement sensor may be provided in a plural number, and a plurality of optical displacement sensors may detect respective displacements with respect to two-axis directions different from one another. Since the external force detecting device incorporates the optical displacement sensors according to the present invention, the adjustment work about the device can be performed easily in a reduced time.

Problems solved by technology

Specifically, in the alignment work, while positional adjustment with respect to the X- and Y-axis directions is easy, rotational adjustment about a Z-axis perpendicular to the X- and Y-axes (to precisely bring the cross-shaped boundary formed by the four PD's 108a in line with the X- and Y-axes) is very difficult

This involves a lot of works, and requires an immense amount of time and effort, especially when displacement amount is large.

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